Simplify setting path to Flutter. #130042
Description
Bigger issue: #122148
- initial design: go/setup-path-with-flutter-extension
- initial verison
- clone flutter if it is missing: Offer to "git clone" the Flutter repo to a location of users choice if no SDK is found (and "git" is available) Dart-Code/Dart-Code#4532 (comment)
- setup path for windows: Add a command to "Add SDK to Path" and offer to invoke it automatically after downloading an SDK [Windows] Dart-Code/Dart-Code#4604
- offer link to documentation for manual setup
- adjustments: go/flutter-setting-path-next-steps
- improvements:
- setup path form macos: Support automatically adding to PATH on macOS Dart-Code/Dart-Code#4612